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Monday, February 24, 2020

Can "clean energy' -- wind and solar — replace hydrocarbons ?

The answer is no,
based on physics.

The answer is yes,
based only on
wishful thinking !


Maximum 
wind and solar 
efficiencies 
remain 
subordinate 
to old rules 
of nature.

Their current 
performance 
leaves little room 
for future gains.

The physics 
boundary for 
a wind turbine, 
the Betz Limit, 
is a 
maximum capture 
of 60% of the
kinetic energy 
in moving air. 

Commercial 
wind turbines
can exceed 40%
... when the wind 
is blowing.


The physics boundary 
for silicon photovoltaic 
(PV) cells, is called the 
Shockley-Queisser Limit, 
a maximum conversion 
of 34% of solar photons
into electrons. 

The best commercial 
PV technology today 
exceeds 26%.



The modern 
wind turbine 
was made possible by
hydrocarbon-based 
fiberglass blades.


An Exxon 
researcher
invented the 
lithium battery 
... containing 
minerals
obtained by 
hydrocarbon
-fueled mining.



Hydrocarbons 
can produce energy 
when needed. 

The best wind 
and solar systems,
in optimum locations,
produce energy 
only 25%-30% 
of the time, or less,
averaged over a year. 

Conventional 
natural gas
plants have 
availability in the 
80%-95% range, 
and often higher.


Every kWh of intermittent 
wind and solar output, 
requires an equal backup 
fossil fuel supply, to keep 
the power grid balanced. 

Plus high costs of 
long transmission lines 
to rural solar and wind 
farms.

And power losses
from transferring 
electricity from 
remote rural sites 
to urban areas.



World energy 
consumption 
continues 
to increase, 

Wind and solar
account for only 2% 
of global demand.

Meanwhile, 
hydrocarbons, 
oil, natural gas, 
and coal, 
supply 84% 
of global energy.